Weighted-average spectra toward the SW image of PKS 1830−211, combining all visits in 2016. The hyperfine structure is shown for each CH Λ-doublet, with the strongest hfs component set at a velocity v = 0 km s⁻¹, or as indicated otherwise. There are two boxes for each line, the first one showing the whole absorption spectrum and the second one showing a smaller range around the continuum level. Best-fit of the CH and ¹³CH absorption is shown in red.